1. Field of the Invention
The present invention relates to a method and system for replacing a lighting system in a microplate reader with a new light source. Specifically the present invention relates to a system which can be used to replace a water cooled laser with an LED light system in an existing microplate reader.
2. Description of Related Art
The use of fluorescence analytical monitoring techniques is well known. Fluorescence measurements can be taken by shining a light source of a first wavelength and then when the sample of light is absorbed the test material is induced to emit light of a second wavelength. Measurement of the second wavelength light, either as length or intensity or the like, can be used to correlate the activity in a cell that is producing the secondary fluorescence. Physiological parameters can then be determined based on the results, such as potassium or other ion channel activity. Florescence type measurements are of great importance to the research and development of new pharmaceutical compositions and are used to screen a variety of tissues for interaction with most any chemical composition that is of interest in affecting the measurable systems.
Typically in the analysis of cells, a variety of older machines are available for using this type of technique with 96 or 384 well multiple well plates. These machines provide a multiwall plate holder, a water cooled laser light source and some form of a receiving camera for detecting the cell second wavelength light emissions. The cells are cultured in each of the wells at the bottom with a growth medium provided over the growing cells. The chemical compound to be tested or otherwise assayed is played into the liquid in each well with the florescent material and the effect measured by excitation by the laser and reading by the camera. For example, in U.S. Pat. No. 5,355,215 to Schroder et al issued Oct. 11, 1994 there is disclosed a method for aligning a camera and a light source for measuring the second wavelength with a minimum about if interference from the supernate liquid. This process has been utilized extensively and appears in later machines and in more recently issued patents, for example in U.S. Pat. No. 7,265,829 issued Sep. 4, 2007 to Jiang et al.
The older machines that utilized water cooled lasers, while difficult to use, were well built and very cost effective. Such machines include the Flipr2® and Flipr3® microplate readers. These machines suffered from the difficulty of using and operating water cooled lasers, but because parts were relatively accessible for repair a burgeoning business in repair and refurbishment developed to keep these machines in service. Since the refurbishment of even a patent product is allowable, repair has been accomplished not only by OEMs but a variety of small companies also repair these types of machines.
Newer machines are very costly and tend to be large in an attempt to avoid the difficulties in using water cooled lasers. An example is the Fliprtetra® made by the same company as the older machine, Molecular Devices (MDC). In order to encourage business for themselves MDC has declined to support its older machines and encourages users of the older machines to upgrade. However, for many users the older machines are fine and there is a desire in the marketplace to continue refurbishing these machines. The fact that water cooled lasers that these machines were built to utilize are expensive, hard to use and getting scarce to fit the existing machines, has suggested the repair life of these machines is limited in spite of the desire of users to continue using the machines to the end of their useful life.
LED's are well known and can be obtained in both regular and high output varieties. However, as a light source multiple LEDs tend to produce a non-homogeneous light and while the availability of machines made from scratch and designed to be used with LED light sources has been accomplished, the use of LEDs in machines not designed for this type of light source has been avoided in retrofit situations because of the problems in providing proper lumen intensity, homogeneousity and coverage in a machine designed for an entirely different type of light source.